The EP9302 Ethernet LAN controller incorporates all the logic needed to interface directly to any MII compatible Ethernet PHY chip. A low-power Micrel KS8721 chip is used to implement the Ethernet PHY function and an integrated RJ-45 connector with built-in 10/100 transformer and LED indicators completes the Ethernet sub-system.
This board has both a LINK/ACTIVITY LED and a 10/100 speed LED built into each RJ-45 connector that indicates the current Ethernet status. The LINK LED (left side of connector, green) is active when a valid Ethernet link is detected. This LED should be ON whenever the board is powered and properly connected to a 10/100BaseT Ethernet network. The LINK/ACTIVITY LED will blink to indicate network activity for either inbound or outbound data. The SPEED LED (right side of connector, amber) will be on when a 100Mb network is detected and off for a 10Mb network. Both of these LEDs are controlled by the KS8721 and do not require any overhead by the processor.
The Ethernet PHY chip can be powered down, under software control, to save approximately 90 mA of current consumption. This is controlled by the EP9302 Digital output on Port H, bit 2. A logic zero will power down the KS8721 PHY interface.